Soybean cultivar S28-V8

ABSTRACT

The invention is a novel soybean cultivar designated S28-V8 with high yield potential and tolerance to Roundup herbicide. The invention relates to seeds of the cultivar S28-V8, plants of the cultivar S28-V8, and to methods for producing a soybean plant produced by crossing the soybean S28-V8 by itself or another soybean genotype.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinctive soybean cultivar,designated S28-V8.

There are numerous steps in the development of any novel, desirableplant germplasm. Plant breeding begins with the analysis and definitionof problems and weaknesses of the current germplasm, the establishmentof program goals, and the definition of specific breeding objectives.The next step is selection of germplasm that possess the traits to meetthe program goals. The goal is to combine in a single variety animproved combination of desirable traits from the parental germplasm.These important traits may include higher seed yield, resistance todiseases and insects, better stems and roots, tolerance to drought andheat, and better agronomic quality.

Choice of breeding or selection methods depends on the mode of plantreproduction, the heritability of the trait(s) being improved, and thetype of cultivar used commercially (e.g., F₁ hybrid cultivar, purelinecultivar, etc.). For highly heritable traits, a choice of superiorindividual plants evaluated at a single location will be effective,whereas for traits with low heritability, selection should be based onmean values obtained from replicated evaluations of families of relatedplants. Popular selection methods commonly include pedigree selection,modified pedigree selection, mass selection, and recurrent selection.

The complexity of inheritance influences choice of the breeding method.Backcross breeding is used to transfer one or a few favorable genes fora highly heritable trait into a desirable cultivar. This approach hasbeen used extensively for breeding disease-resistant cultivars. Variousrecurrent selection techniques are used to improve quantitativelyinherited traits controlled by numerous genes. The use of recurrentselection in self-pollinating crops depends on the ease of pollination,the frequency of successful hybrids from each pollination, and thenumber of hybrid offspring from each successful cross.

Each breeding program should include a periodic, objective evaluation ofthe efficiency of the breeding procedure. Evaluation criteria varydepending on the goal and objectives, but should include gain fromselection per year based on comparisons to an appropriate standard,overall value of the advanced breeding lines, and number of successfulcultivars produced per unit of input (e.g., per year, per dollarexpended, etc.).

Promising advanced breeding lines are thoroughly tested and compared toappropriate standards in environments representative of the commercialtarget area(s) for three or more years. The best lines are candidatesfor new commercial cultivars; those still deficient in a few traits maybe used as parents to produce new populations for further selection.

These processes, which lead to the final step of marketing anddistribution, usually take from eight to 12 years from the time thefirst cross is made. Therefore, development of new cultivars is atime-consuming process that requires precise forward planning, efficientuse of resources, and a minimum of changes in direction.

A most difficult task is the identification of individuals that aregenetically superior, because for most traits the true genotypic valueis masked by other confounding plant traits or environmental factors.One method of identifying a superior plant is to observe its performancerelative to other experimental plants and to a widely grown standardcultivar. If a single observation is inconclusive, replicatedobservations provide a better estimate of its genetic worth.

The goal of a plant breeding is to develop new, unique and superiorsoybean cultivars and hybrids. The breeder initially selects and crossestwo or more parental lines, followed by repeated selfing and selection,producing many new genetic combinations. The breeder can theoreticallygenerate billions of different genetic combinations via crossing,selfing and mutations. The breeder has no direct control at the cellularlevel. Therefore, two breeders will never develop the same line, or evenvery similar lines, having the same soybean traits.

Each year, the plant breeder selects the germplasm to advance to thenext generation. This germplasm is grown under unique and differentgeographical, climate and soil conditions, and further selection arethen made, during and at the end of the growing season. The cultivarswhich are developed are unpredictable. This unpredictability is becausethe breeder's selection occurs in unique environments, with no controlat the DNA level (using conventional breeding procedures), and withmillions of different possible genetic combinations being generated. Abreeder of ordinary skill in the art cannot predict the final resultinglines he develops, except possibly in a very gross and general fashion.The same breeder cannot produce the same cultivar twice by using theexact same original parents and the same selection techniques. Thisunpredictability results in the expenditure of large amounts of researchmonies to develop superior new soybean cultivars.

The development of new soybean cultivars requires the development andselection of soybean varieties, the crossing of these varieties andselection of superior hybrid crosses. The hybrid seed is produced bymanual crosses between selected male-fertile parents or by using malesterility systems. These hybrids are selected for certain single genetrains such as pod color, flower color, pubescence color or herbicideresistance which indicate that the seed is truly a hybrid. Additionaldata on parental lines as well as the phenotype of the hybrid influenceto breeder's decision whether to continue with the specific hybridcross.

Pedigree breeding and recurrent selection breeding methods are used todevelop cultivars from breeding populations. Breeding programs combinedesirable traits from two or more cultivars or various broad-basedsources into breeding pools from which cultivars are developed byselfing and selection of desired phenotypes. The new cultivars areevaluated to determine which have commercial potential.

Pedigree breeding is used commonly for the improvement ofself-pollinating crops. Two parents which possess favorable,complementary traits are crossed to produce an F₁. An F₂ population isproduced by selfing one or several F's. Selection of the bestindividuals may begin in the F₂ population; then, beginning in the F₃,the best individuals in the families are selected. Replicated testing offamilies can begin the F₄ generation to improve the effectiveness ofseletion for traits with low heritability. At an advanced stage ofinbreeding (i.e., F₆ and F₇), the best lines or mixtures ofphenotypically similar lines are tested for potential release as newcultivars.

Mass and recurrent selections can be used to improve populations ofeither self- or cross-pollinating crops. A genetically variablepopulation of heterozygous individuals is either identified or createdby intercrossing several different parents. The best plants are selectedbased on individual superiority, outstanding progeny, or excellentcombining ability. The selected plants are intercrossed to produce a newpopulation in which further cycles of selection are continued.

Backcross breeding has been used to transfer genes for a simplyinherited, highly heritable trait into a desirable homozygous cultivaror inbred line which is the recurrent parent. The source of the trait tobe transferred is called the donor parent. The resulting plant isexpected to have the attributes of the recurrent parent (e.g., cultivar)and the desirable trait transferred from the donor parent. After theinitial cross, individuals possessing the phenotype of the donor parentare selected and repeatedly crossed (backcrossed) to the recurrentparent. The resulting plant is expected to have the attributes of therecurrent parent (e.g., cultivar) and the desirable trait transferredfrom the donor parent.

The single-seed descent procedure in the strict sense refers to plantinga segregating population, harvesting a sample of one seed per plant, andusing the one-seed sample to plant the next generation. When thepopulation has been advanced from the F₂ to the desired level ofinbreeding, the plants from which lines are derived will each trace todifferent F₂ individuals. The number of plants in a population declineseach generation due to failure of some seeds to germinate or some plantsto produce at least one seed. As a result, not all of the F₂ plantsoriginally sampled in the population will be represented by a progenywhen generation advance is completed.

In a multiple-seed procedure, soybean breeders commonly harvest one ormore pods from each plant in a population and thresh them together toform a bulk. Part of the bulk is used to plant the next generation andpart is put in reserve. The procedure has been referred to as modifiedsingle-seed descent or the pod-bulk technique.

The multiple-seed procedure has been used to save labor at harvest. Itis considerably faster to thresh pods with a machine than to remove oneseed from each by hand for the single-seed procedure. The multiple-seedprocedure also makes it possible to plant the same number of seeds of apopulation each generation of inbreeding. Enough seeds are harvested tomake up for those plants that did not germinate or produce seed.

Descriptions of other breeding methods that are commonly used fordifferent traits and crops can be found in several reference books(e.g., Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987).

Proper testing should detect any major faults and establish the level ofsuperiority or improvement over current cultivars. In addition toshowing superior performance, there must be a demand for a new cultivarthat is compatible with industry standards or which creats a new market.The introduction of a new cultivar will incur additional costs to theseed producer, the grower, processor and consumer, for specialadvertising and marketing, altered seed and commercial productionpractices, and new product utilization. The testing proceeding releaseof a new cultivar should take into consideration research anddevelopment costs as well as technical superiority of the finalcultivar. For seed-propagated cultivars, it must be feasible to produceseed easily and economically.

Soybean, Glycine max (L), is an important and valuable field crop. Thus,a continuing goal of plant breeders is to develop stable, high yieldingsoybean cultivars that are agronomically sound. The reasons for thisgoal are obviously to maximize the amount of grain produced on the landused and to supply food for both animals and humans. To accomplish thisgoal, the soybean breeder must select and develop soybean plants thathave the traits that result in superior cultivars.

SUMMARY OF THE INVENTION

The invention is a novel soybean cultivar designated S28-V8 with highyield potential and tolerance to Roundup herbicide. The inventionrelates to seeds of the cultivar S28-V8, plants of the cultivar S28-V8,and to methods for producing a soybean plant produced by crossing thesoybean S28-V8 by itself or another soybean genotype.

DEFINITIONS

In the description and tables which follow, a number of terms are used.In order to provide a clear and consistent understanding of thespecification and claims, including to scope to be given such terms, thefollowing definitions are provided:

Maturity Date. Plants are considered mature when 95% of the pods havereached their mature color.

Seed Yield (Bushels/Acre). The yield in bushels/acre is the actual yieldof the grain at harvest.

Lodging Resistance. Lodging is rated on a scale of 1 to 9. Where one iscompletely upright and 9 is completely prostrate.

Emergence. This score indicates the ability of the seed to emerge whenplanted 3" deep in sand and with a controlled temperature of 25° C. Thenumber of plants that emerge each day are counted. Based on this data,each genotype is given a 1 to 5 score based on its rate of emergence andpercent of emergence, an intermediate score of 2.5 indicates averageratings and a 5 score indicates a very poor rate and percent ofemergence.

Iron-Deficiency Chlorosis. Plants are scored 1 to 9 based on visualobservations. A score of 1 means no stunting of the plants or yellowingof the leaves and a score of 9 indicates the plants are dead or severelystunted due to iron-deficiency chlorosis.

Brown Stem Rot. Plants are scored from 1 to 9 by visually comparing allgenotypes in a given test. The score is based on leaf symptoms ofyellowing and necrosis caused by brown stem rot. A score of 1 indicatesno symptoms. Visual scores range to a score of 9 which indicates severesymptoms of leaf yellowing and necrosis.

Sudden Death Syndrome. Plants are scored from 1 to 9, with 1 indicatingno symptoms and 9 indicating severe leaf symptoms.

Shattering. The amount of pod dehiscence prior to harvest. Poddehiscence involves seeds falling from the pods to the soil. This is avisual scene from 1 to 9 comparing all genotypes within a given test. Ascore of 1 means pods have not opened and no seeds have fallen out. Ascore of 9 indicates 100% of the pods are opened.

Plant Height. Plant height is taken from the top of soil to top of nodeof the plant and is measured in centimeters.

DETAILED DESCRIPTION OF THE INVENTION

Parentage: S 30-06 (2)×(S 28-01 (2)×40-3-2). S 30-06 and S 28-01 arecommercial cultivars developed by Novartis (Northrup King). 40-3-2 is aline developed by Monsanto which carries their patented gene conferringtolerance to Roundup Herbicide. Seed of S 28-01 was supplied to Monsantoto make the initial cross to 40-3-2 and one backcross. This BC1F1 wasplanted at the NK Research Center at Waimea, Kauai, Hi., in December of1992. Plants from this F1 population were sprayed with Roundup to removesusceptible plants. Resistant plants were used as males to cross onto S30-06. Seeds from this cross (numbered JX2459) were planted at the NKResearch Center at St. Joseph, Ill., in May of 1993. F₁ plants weresprayed with Roundup, and resistant survivors were used as males inmaking a backcross onto S 30-06 (cross JX2656). Seeds from this crosswere planted at Waimea in December of 1993. F₁ plants were again sprayedwith Roundup and harvested in February, 1994 . The BC1F2 population wasplanted in March at Waimea, sprayed with Roundup at the vegetativestage, and harvested in June by picking 2-3 pods from each resistantplant. The resulting F₃ population was planted at St. Joseph in June,1994, and again sprayed prior to flowering. Individual F₃ plants wereharvested in October, threshed individually, and grown in preliminaryyield trials at St. Joseph and the NK Research Center at Washington,Iowa, in the summer of 1995. One of these, designated J441211, wasselected based on yield, uniformity, and homogeneity for tolerance toRoundup for further testing and seed increase. This line was extensivelytested in 1996 and released as S28-V8.

Some of the criteria used to select in various generations include; seedyield, lodging resistance, emergence, disease tolerance, maturity, lateseason plant intactness, plant height and shattering resistance.

The cultivar has shown uniformity and stability for all traits, asdescribed in the following variety description information. It has beenself-pollinated a sufficient number of generations, with carefulattention to uniformity of plant type to ensure homozygosity andphenotypic stability. The line has been increased with continuedobservation for uniformity. No variant traits have the followingmorphologic and other characteristics:

    ______________________________________    Plant Types & Habit:                  Slender    Flower color:                                         Purple    Hypocotyl Color:                  Light Purple                             Pod color:  Brown    Leaflet Shape:                  Ovate      Hilum color:                                         Gray    Stem Termination:                  Indeterminate                             Seed Coat Color:                                         Yellow    Plant Pubescence color:                  Gray       Cotyledon color:                                         Yellow    Seed Protein Peroxidase    Activity:    Phytophthiora Res. Gene:                  Rps 1-a    Maturity Group                  II    Relative Maturity:                  II-8    Average Seeds Per Pound:                  2400    ______________________________________

This invention is also directed to methods for producing a soybean plantby crossing a first parent soybean plant with a second parent soybeanplant, wherein the first or second soybean plant is the soybean plantfrom the line S28-V8. Further, both first and second parent soybeanplants may be from the cultivar S28-V8. Therefore, any methods using thecultivar S28-V8 are part of this invention; selfing, backcrosses, hybridbreeding, and crosses to populations. Any plants produced using cultivarS28-V8 as a parent are within the scope of this invention. As usedherein, the term "plant" includes plant cells, plant protoplasts, plantcells of tissue culture from which soybean plants can be regenerated,plant calli, plant clumps, and plant cells that are intact in plants orparts of plants, such as pollen, flowers, seeds, pods, leaves, stems,and the like. Thus, another aspect of this invention is to provide forcells which upon growth and differentiation produce the cultivar S28-V8.

                  TABLES    ______________________________________    S28-V8 was tested in the NK Advanced Group II Late Yield Trial    in 1996. Data were collected for yield (bushels per acre),    maturity (date), lodging score (1 = completely upright,    9 = completely prostrate), plant height (cm.), iron    deficiency chlorosis score (1 = no chlorosis, 9 =    severe chlorosis and plant stunting), and pod shatter    score (1 = no shatter, 9 = all pods    shattered). Data are summarized in the following table.           Yield   Maturity Lodging                                  Height                                        Chlorosis                                               Shatter    Variety           Ave. 19 Ave. 11  Ave. 13                                  Ave. 4                                        Ave. 2 Ave. 3    ______________________________________    S28-V8 47.3    9-29     1.6   79    6.1    1.4    S 30-06           51.4    10-1     2.1   90    5.9    2.0    A2242  47.1    9-26     2.8   71    5.8    4.2    Pio. 9273           48.9    9-26     2.6   72    4.5    2.3    Pio. 9281           49.4    9-29     2.5   72    5.0    1.9    S 24-92           49.5    9-24     2.7   72    5.7    3.8    LSD .05           2.5     1        0.5    6    2.6    0.9    ______________________________________

DEPOSIT INFORMATION

A deposit of the soybean seed of this invention is maintained byNovartis Corporation, 3054 Cornwallis Road, Research Triangle Park,N.C., 27709. Access to this deposit will be available during thependency of this application to persons determined by the Commissionerof Patents and Trademarks to be entitled thereto under 37 C.F.R. § 1.14and 35 U.S.C. § 122. Upon allowance of any claims in this application,all restrictions on the availability to the public of the variety willbe irrevocably removed by affording access to a deposit of at least2,500 seeds of the same variety with the American Type CultureCollection, 10801 University Blvd, Manassas, Va. 20110-2209, ATCCAccession Number 203507.

What is claimed is:
 1. A soybean seed designated S28-V8 (ATCC AccessionNumber 203507).
 2. A plant or plants of the soybean cultivar designatedS28-V8 produced by growing the seed of claim
 1. 3. Pollen of the plantof claim
 2. 4. Ovule or ovules of the plant of claim
 2. 5. A soybeanplant with all of the physiological and morphological characteristics ofthe soybean plant of claim
 2. 6. Tissue culture of the plant of claim 2.7. A soybean plant regenerated from the tissue culture of claim 6wherein the regenerated soybean plant has all of the physiological andmorphological characteristics of a plant grown from a soybean seeddesignated S28-V8.
 8. A method to produce a hybrid soybean seedcomprising the steps of:a) planting in pollinating proximity seeds ofsoybean cultivar S28-V8 (ATCC Accession Number 203507) and anothersoybean cultivar; b) cultivating soybean plants resulting from saidseeds until said plants bear flowers; c) emasculating the plants ofeither one or the other soybean cultivar; d) inducing cross pollinationto occur between said soybean cultivars; and e) harvesting seedsproduced on said emasculated plants of the cultivar line.
 9. A firstgeneration (F₁) hybrid soybean plant produced by growing said hybridsoybean seed of claim 8.